March 25, 1948: The First Tornado Forecast
In 1884, John Finley of the United States Army Signal Service published a brief article in the American Meteorological Journal titled “Tornado Predictions.” In this article, he presented the results of a study that suggested that the occurrence of tornadoes could be predicted over segmented areas of the central and eastern United States, up to eight hours in advance, with probabilities exceeding 95%. It would be more than half a century, however, before the concept of operational tornado forecasting would be put to practical use. In fact, the weather forecasting and warning division of the Signal Service—along with its civilian successor, the U.S. Weather Bureau—would maintain a longstanding policy prohibiting the use of the word “tornado” in official forecasts or warnings. The reason for this, as stated in the 1887 annual report of the Chief Signal Officer, is that even if forecasters could accurately predict a tornado's occurrence in a particular state or county, “it is believed that the harm done by such a prediction would eventually be greater than that which results from the tornado itself.”
Contributing Editor SEAN POTTER is a Certified Consulting Meteorologist (CCM), Certified Broadcast Meteorologist (CBM), and science writer with an interest in weather history.